Clutch control mechanism



llllllll 'INVENTOR.

& TTORNEYS.

ROY 5. SANFORD BY w '1l/111011111111111,un,

Feb'. 27, 1940. R. s. SANFORD CLUTCH CONTROL MECHANISM Filed Dec. 1.1932 Patented Feb. 27, 1948 nay s. Sanford,

Bendix Aviation Collilaon,

South Bend. Ind., assignor to 'South Bend,

Ind., a corporation of Delaware Appucnunn December 1, 1932, serial No.645,298

' A4 claims. (o1. 19a-01) the spool valve forward, cutting ofi thevacuum from the booster cylinder and admitting atmos- Tnis inventionrelates to clutch actuating' mechanism for automotive vehicles and'relates particularly to vacuum operated power means for disengaging theclutch.

An object of the invention is to insure the desired smooth uniformengagement of the clutch at all times regardless of the wear of theclutch plates.

More speciflcally,'an object of the invention is to provide a couplingbetween a booster mechanism and a clutch actuating varm which functionsas an integral unit during .the major portion of the clutch actuatingstroke, and which operates both as a bleed valve and coupling for thebooster cylinder as soon`as the clutch plates have become'engaged.- y

Various other objects and meritorious features of the invention will beapparent from the following description taken in commotion with thedrawing .whereinzl.

Figure lis a diagrammatic illustration ofthe accelerator control forlthe booster mechanism, Figure 2 is a.` sectionalelevationr throughtheboostercylinder and its coupling with the ,clutch actuating arm; and ,y

Figure3 is an enlarged sectional view ofthe control valve of Figure 1'.-

Referring n ow tothe drawing, avacuuxn line i6 extends froml anintakemanifold I2oil a conventional internal-combustion engine;V(notshown) to a booster lcylinder I4, en accelerator controlled valveI6being"inc,orporated insaid line to control the Voperation oifthebooster. -The control valve lI6isof a ktypedescribed in Vdev tail incertain of my. copending,applicationsfand comprises a ycylinder casingin which la spool valve' I8 is slidable, said valve havinga stem 20secured 'thereto and extending rearwardly through the casing. The samestem extends throughv an enlarged opening in a bracket 22 which issecured to the accelerator rod 24, an enlarged head 26v providingraone-way coupling between the bracket and the valve: 25 indicates-aconventional type of accelerator pedal.

A by-pass 28v permits the forward part of the valve casing to beevacuated. In Figure 1 the. valve is illustrated in accelerator releasedposition, the spoolyalve I8 being held in its rearward position andproviding direct communication through the vacuum line I6 to the boostercylinder I4.

move the rod 24 forwardly, releasing the spool valve I8l for movement ina. forward direction and the. atmospheric pressure willY operatethrouslivents III- inthe valve casing to mover apertures 46 and Depression ofthe accelerator will. -discs in engagement.

phere to the booster to effect an engagement of the clutch.

'I'he booster cylinder may be of any preferred construction and shouldbe portion ofthe vehicle chassis,

the pivotal connection at secured to some xed as indicated by 32. Apiston 34 is slidable within the cylinder and secured thereto is apiston stem 36 which extends out from the cylinder a substantialdistance when the piston is at its. forward limit of movement. The saidstem 36 is axially bored as at 38, which bore communicates with spacedapart transverse 42. The the stem is` provided with which may bethreaded in in the drawing.v

extreme outer end of an enlarged head 44,

position as indicated Pivotally secured to a clutch actuating arm 46 isa lvalve casing 4s which is vented to the 'atmosphere at one extremityby means of vents 50. `The arm 46 is connected in the usual manner `to adriven clutch member 5l which is normally urged into engagement with adrivingA clutch member 5I by a spring 53 commonly argranged as shown.These members are shown valve casingl is crimped in diagrammaucal'ly 1nF1g.`2of the drawing. l This as at 52 toproVide-fa shoulder adapted tofunction as a. 'seat for one endof coil spring 54, the other end of saidvvspring seating against the enlarged head 44 positioned at theextremity of the piston stern.k 'Ihe lforwardend vof the valve casing 48represents somewhat a tapered bottle neck 56, adjacent Athe buterextremity of which are a pluralityfo'f air i vents` 58.

illustrated, the vstem 36 isslidable through the bottle neck portion ofthe transverse aperture 42 the valve casing and is adapted to registersubstantially with the vents 58 when the piston 34 has-reached its limitof movement to the left.

T'he vented tapered neck apertured ture operable to control hereinafter.

An important feature of sides in the fact that the 56 together with thestem 36 constitute a bleed valve structhe clutch engaging y operation ofthe booster as descrlbedin detail thiscombination recoil spring 54 issubstantially weaker than the conventional clutch `spring 53 whichnormally ted to hold the clutch When the accelerator pedal is released,and the booster cylinder is in communication with theevacuated intakemanifold through the line to the left without carryin I6, the piston 34will move g the valve casing 48 along with it until the coil spring t@has substantially reached the limit of its yield, at which time the saidcasing qvill be picked up and draw with it the clutch actuating arm itto disengage the clutch. A check valve 55 in one end vented to air ashitherto explained.' As the piston 3 moves to the right the air in thecylinder will escape through the aperture d along the axial bore 38 ofthe stem to the rear aperture t2, and thence out the vents 5B in thevalve casing. The coil spring' 5d being weaker than the clutch spring,the piston stem 36and the valve casing d8 will move asa unit relativelyrapidly until the clutch plates touch one another, at which time thepiston stem 36 will begin to move to the right with respect to the valvecasing d8 and the escape of air through the vents 58 will be graduallyclosed oif as the transverse aperture 42 in the stem approaches the baseof the tapered bottle neck 56. In this way a cushion orrelatively slowclutch engaging action is secured immediately after the clutch plateshave contacted one another with a predetermined load, and it will beapparent that this action will 'take placeregardless of the wear on theclutch plates' and the consequent extent of movement of the valve andstem coupling prior to reaching that point. Th`e relative strength ofthe clutch spring 53 and valve spring 5l determines the aforementionedloading of the clutch and therefore the time of initiation of theaforementioned cushioning or bleed valve action'.

It will therefore be seen that the coupling between the clutch actuatingarm 46 and the vacuum booster mechanism constitutes a bleed valveIv ousmpdications will be readily apparent to those skilled in the art and forthat reason I wish tol limit myself only within the scope oi theappended claims.

IA claim:

-1. In .combination with a spring operated clutch m #fw cylinder havinga end of the cylinder, transverse passages extending into said stemadiacent the piston and at a distance therefrom greater than the lengthoi' said cylinder, an axial bore through said stem communicating withsaid passages, an apertured casing member telescopingly mounted on saidstem at one end thereof and constituting therewith a bleed valvemechanism, yieldable means providing a series connection between saidstem and casing' member, and means interconnecting secured to saidpiston and extending through one said casing with the clutch mechanismto be opj erated. I 1 2. In an au motive vehicle provided with a clutchand with meansrbiasing said4 clutch to closed position, meanscomprisinga suction chamber for disengaging saidclutch, and means, renderedeifective by initial contact of the clutch elements during clutchreengag'in'gimovement to cation between one of the chambersof the motorandthe atmosphere', and a spring biased valve for closing thecommunication through the tu-f bular rod, said valve being held in openposition by relative movement between the rod and arm when the clutch isdisengaged and closed by its spring upon contact of the clutch faceswhen the clutch is permitted to engage.

4. In a motor vehicle, the combination of a clutch, a clutch controllingdevice comprising a cylinder and a piston reciprocable therein, saidcylinder beingclosed to form -a suction chamber at one side of thepiston and a compression choamber at the opposite side, a-clutchoperating element, a tubular rod connected to the' piston at one end andhaving the other end connected to the clutch operating element, a springcom.-

pressed by the actuation of the rod to disengage the clutch, saidtubular rod providing communi- 'l cation between the compression chamberof the cylinder and the atmosphere when said vspring is compressed, anda valve controlled by said' spring and operating to close thecommunication between the compression chamber and the atmosphere whenthe spring is permitted to expand the clutch.

